|
The Canadian Capacity Guide for Signalized Intersections (CCG) is a publication of the Canadian Institute of Transportation Engineers (CITE).〔http://www.cite7.org/index.php〕 It provides a methodology that allows Traffic Engineers to plan, design, and evaluate traffic signal controlled roadway intersections. The CCG has been based on the current experience of practicing traffic engineers, transportation educators and students across Canada, and a considerable body of Canadian and international research. But while developed in Canada, its methodology is applicable to conditions anywhere. The survey procedures included in the CCG provide direction for users in any country to collect local data which can be used to obtain geographically specific results. ==Objectives== Many cities and metropolitan areas experience traffic congestion on some portions of their transportation networks. These municipalities also suffer from constrained urban space and limited financial resources, but they share the desire to improve the quality of their environment. The analytical tools to understand specific problems require refined methods for the evaluation of alternative solutions. Techniques included in the CCG allow Traffic Engineers to analyze various situations and intersection configurations. This Guide emphasizes the importance of a clear definition of the objectives of signal operation at a specific location. It also provides an understanding of the role that the intersection plays in the travel patterns, public transportation, and both motorized and non-motorized modes of transportation. The focus of the CCG is on the movement of traffic flow units, such as cars, trucks, transit vehicles, cyclists, and pedestrians at signalized intersections. The main parameter is the time dimension that determines how efficiently the available roadway space is used by conflicting traffic streams. The allocation of time to the movement of vehicular and pedestrian traffic in lanes and crosswalks influences not only intersection capacity, but also a number of other measures that describe the quality of service provided for the users. To this end, and to provide input to investigations of possible impacts, the Guide provides both analytical and evaluation methods, and a set of up-to-date numerical parameters for Canadian conditions. Using the Guide, it is possible to assess a variety of solutions by application of a set of practical evaluation criteria. The evaluation criteria, or measures of effectiveness, provide the user with a comprehensive account of intersection operation. Two of the key measures of effectiveness are total person delay and delay to pedestrians. These criteria are essential as the prerequisites for an equitable treatment of all modes of transportation, especially public transit. Other performance measures relate the Guide to environmental, economic and safety analyses, and serve as vital information for transportation demand modelling. Delay and the ratio of volume to capacity are two key parameters widely used in the profession to assess the performance of an intersection. The Guide focuses on the ratio of volume to capacity as a rational measure of how well the intersection is accommodating demand, but it is acknowledged that delay is also widely used (for example, in the Highway Capacity Manual). Whether one parameter or the other is the most relevant is the subject of ongoing debate in the profession. It is advisable to consider both parameters in the assessment of an intersection, at the level of the individual movement, the approach and the intersection as a whole. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Canadian Capacity Guide For Signalized Intersections」の詳細全文を読む スポンサード リンク
|